US Patent 7373057 Telecommunication loose tube optical cable with reduced diameter

An optical fiber cable has a highly reduced diameter. The cable has a central strength member; a number of tubes containing loosely arranged optical fibers, each tube having a thickness, and each optical fiber having a coating; and a protective outer jacket, wherein the filling coefficient of optical fibers in at least one loose tube is ≧45°/0. The tubes are made of a material having an elasticity modulus ≧700 MPa; and the optical fibers are SM-R fibers having a microbending sensitivity ≦4.0 dB·km−1/g·mm−1 at a temperature of about −30° C. to +60° C. at about 1550 nm.